Telephone-exchange system.



i. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB-8. 1912.

1,205,499. I Patnted Nov. 21, 1916.

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J. L. WRIGHT.

Patented Nov. 21, 1916.

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J. L. WRIGHT. TELEPHONE EXCJHAN'GE SYSTEM. JAPPLICATION FILED FEB. 8,1912.

Patented Nov. 21, 1916.

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J, L. WRIGHT. IELEPHONE EXCHANGE SYSTEM.

APPllCATlON FILED FEB. 8,1912- 1 SHEETS-SHUT 4.

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 8. m2.

1,205,499. Patented-Nov. 21,1916.

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.I. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. B, 1912.

UNITED STATES PATENT ornron.

JOSEPH L. WRIGHT, OF VVASH-INGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BYMESNE ASSIGNMENTS, T0 JAMES R. GARFIELD, TRUSTEE, OF CLEVELAND, OHIO.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Nov. 21, 1916.

Application filed February 8, 1912. Serial No. 676,395.

To all whom it may concern:

Be it known that I, Josnrrr L. .IVRIGHT, a citizen of the United States,and resident of Washington, District of Columbia, have invented certainnew and useful Improvements in Telephone-Exchange Systems, of which thefollowing is a specification.

My invention relates to telephone exchange systems, and has for itsobject the provision of an improved means in recording or indicatingcalls between exchanges or switching stations.

In trunking between exchanges, I use what I term indicating trunks asthey terminate at one end in indicators or number wheels associated withplugs, jacks or other connecting means. These indicators are locatedbefore a B or trunking operator and are controlled by an A operator, whofirst receives the call.

The A operator is provided with a suitable sending device and uponreceiving a call for another exchange, manipulates her sending device,causing the indicators to register the'number of the desired line.

The indicators have associated signal lamps which notify the B operatorthe condition of the connection.

Another feature of my invention consists in providing a selectiveringing device, associated with the indicators and also controlled bythe A operator. This device, instead of operating a number wheel,actuates sets of contact springs by suitable cam arrangements.

In the present case, I have shown the indicators and ringing devicesassociated with trunks terminating in plugs and cords before the Boperator. The ringing is automatic, and the duties of the B operator arereduced to a minimum, as she merely picks up the plug associated withthe inclicator and places it into the jack of the desired line.

In the accompanying drawings, I have" from manual to manual exchanges orfrom a full automatic to a manual exchange.

My invention is illustrated in the accompanying drawings, wherein:

Figure 1 shows a line and control circuit. Fig. 2 shows primary andfirst selector switch circuits. Fig. 3 shows an indicating trunk at amanual exchange. Fig. t shows a subs cribers line circuit at a manualexchange. Fig 5 shows the key-set control circuit. Fig. 6 shows anoperators key-set switch'circuit. Fig. 7 shows an operators keyboard andsending device.

Referring now to Fig.1,the subscribers station is equipped withapparatus usual in common battery systems. The line wires from thesubscribers station terminate in the central oflicein the line relay 2.The line relays are divided into groups, there being ten groups to eachone hundred lines. Each group of ten line relays is common to one grouprelay 3. The group relay, when actuated, makes the row contact in theprimary. switch busy, while the line relay, when actuated, makes theindividual contact in the primary selector switch'busy. The

switch W starts to rotate whenever the group relay is energized, andcontinues to rotate until an idle primary switch is picked out. I Vhensuch an idle primary switch is picked out, it first starts to rotateuntil the row wiper picks out the busy row contact and after reachingthis contact it ceases to rotate and steps vertically until theindividual busy test contact is found.

Referring now,to Fig. 2, the primary switch C is shown, which picks outthe calling line. The first selector switch is shown at D, whichresponds to impulses from the sending device and picks out an idleindicating trunk leading to a manual exchange. Wipers 63 of the primaryswitchC and wipers 56 of the first selector switch D are joined asindicated by the heavy lines, for conversational purposes The tip andsleeve conductors are separated by the condensers 43 and 4%. Throughrelay 23 and the retardation coil 26 talking current is supplied to thecalling subscriber. vRelay 21 is the starting relay for the primaryswitch, and

also corresponds to the line relay (Fig. 1) in that it controls theaction of the operators key-set switch (Fig. 6). Relay 22 is the rowtest relay, while 25! is the individual test relay. Relay 25 is operatedwhen the key-set switch picks out the trunk, and remains energized whilethe impulses are being transmitted, thereby opening the trunkconductors. Relay 27 is the test relay used in connection with the firstselector switch for picking out an idle trunk. Relay 28 is energizedwhenever either the rotary or vertical magnets of the primary switch areoperated and also when the vertical magnet of the first selector switchis operated. The circuits of these magnets are normally completedthrough the back contacts of this relay 28 and so, therefore, when it isactuated the magnet circuits are opened. The action of this relay andthe magnets cause the latter to vibrate and to continue to do so untilthe energizing circuit is opened.

Referring now to Fig. 3, the indicating trunk consists of the numberwheels controlled by their stepping magnets, shown at H, I, J. Theselective ringing device is shown at K in its normal or restingposition. At the first step of the magnet 102, the cam 100 closes thesprings 103 and 102k, thereby connecting number 1 generator to thecontact of the ringing relay 95. At the second step, the contacts 10%and 103 are broken and contacts 106 and 107 are closed by the cam 101.At the third step, the springs 103 and 105 are closed by the cam 100,and the springs 106 and 107 are then opened by the cam 101. At thefourth step, he springs 107 and 108 are closed by the cam 101, whilesprings 103 and 105 are opened by the cam 100. From the foregoing, itwill be seen that the generators are cut on in regularordercorresponding to the number of impulses transmitted. The number wheelsor indicators and the selective ringing device are cut on in properorder by means of the shifting switch shown at X. This switch iscontrolled and made to step forward one step by the action of therepeating relay 81. This latter relay responds to impulses from thesending device. Relay 98 also responds to impulses from the sendingdevice and operates the various number wheels and the selective ringingdevice in proper order through the contacts of the switch X' The tip andsleeve conductors from the semiautomatic exchange lead to a twoconductor plug, shown at PP. These conductors are separated by means ofthecondensers 91 and 92, and the repeating coil 93. Through the relays83 and 8% talking current is supplied to the called subscribers line.The ringing relay 95 is controlled by the commutator 90. The lamp S7 islighted when the indicators have been operated and notifies the Boptrunk.

erator of the call. The supervisory lamp 86 notifies the operator whenthe called subscriber answers. Relay S5 is actuated by the relay 83 whenthe called subscriber answers, and prevents any further action of theringing relay.

Fig. a shows a subscribers line circuit in the manual exchange, and isvery similar to that shown in Fig. 1, the main difference being that itis what is commonly known as a two wire circuit.

Referring now to Fig. 5, the switch Y acts in the same manner as theswitch (Fig. 1) but instead of picking out a primary switch, it picksout an idle operators keyet switch.

Referring to Figs. 6 and 7, the key-set switch is shown at M. The wipers167 connect to the tip and sleeve sides of the first selector in Fig. 2,over which the operator converses with the calling subscriber and overwhich the impulses are transmitted. 168 is the row wiper and picks outthe group of ten in which the calling trunk is located. Relay 15 1 isconnected to the individual test viper, which picks out the particulartrunk in the group calling. Relay 156 is the signal relay and pulls upin series with relay 25 (Fig. 2) when the trunk is picked out, and whenenergized closes the circuits of the two lamps 2st?) and 2st (Fig. 7notifying the operator. of a call. 152 is the starting relay andcorresponds to relay 21 (Fig. 2) while 153 is the row test relay. Relay155 responds when the operator presses the answering button 24:8,thereby connecting her telephone-set across the tip and sleeveconductors of the trunk. 157 is actuated when the operator presses Relay7 the starting button 247. The action of this relay disconnects relay155 and connects the starting wire controlled by the cam 231 to thestepping magnet 161, thereby causing the switch arms to step over thebanks N, O, P. This stepping magnet is operated once at each rotation ofthe sending device and cuts on the impulses from the keyboard (Fig. 7)in regular order. The order in which these impulses are transmitted isas follows: At the first rotation of the sending device, the impulsescorresponding to the thousands are sent over the tip side of the trunk.t the second rotation, a single test impulse is sent over the sleeveside of the At the third rotation, impulses corresponding to thehundreds are sent over the tip side of the trunk, and at the fourthrotation, a single test impulse is sent over the sleeve side of thetrunk, etc. The order in which these impulses are sent is uniform,'

there being a single test impulse interposed between each set of thenumeral impulses. After the last impulse has been sent, the

wiper passing over the bank of contacts P,

closes the circuit of relay 158, causing the switch to rapidly rotateuntil it reaches its normal position. normal position, however, theCircuit of the release magnet 166, of the key-set switch M, isenergized, thereby releasing this switch and preventing the operatorlistening in or interfering with a connection. Relay 163 corresponds torelay 28, (Fig. 2), and causes the magnets 164 and 165 to vibrate untiltheir energizing circuits are opened.

The operators keyboard, shown in Fig. 7 consists of five rows of buttonseach row having ten buttons. Number 1 button of each row is connected toa contact operated by the cam 232. Number 2 button of each row isconnected to the contact operated by the cam 233. Corresponding buttonsineach row are connected to the same contact. The contact controlled bythe cam 232 is closed just long enough to keep the relay 160 (Fig. 6)energized while one impulse is being transmitted by the impulse wheel242. If Number 10 button were down, relay 160 would be closed by the cam241 just long enough for ten impulses to be transmitted by the impulsewheel 242. The contacts of the impulse wheel 242 are connected directlyto the normally open contact of relay 160, and when this relay isenergized, the impulses are connected to either the tip or sleeve sideof the trunk, depending upon the position of the arm in regard to thecontacts of the bank N. The buttons or keys shown in these five rows inFig. 7, are of the usual locking and indicating type. When any onebutton of a certain row is depressed, it will release the buttonformerly depressed.

The buttons 246, 247 and 248 are of the non-locking type and thecontacts controlled by them are only closed while the operator isressing the button.

Other points in connection with the various figures will be brought outin the detailed description of the operation.

The operation of my system is as follows: The subscriber A, uponremoving his receiver closes the circuit of the line relay 2 in serieswith the group relay 3. The relay 3 operating closes the circuit, of therelay 4, which in turn connects ground to one terminal of the relay 5,and also closes the circuit of the stepping magnet 7. The steppingmagnet 7 operating closes the circuit of relay 6, which in turn opensthe circuit of magnet 7, causing it to vibrate and step around the wiperof the switch This switch will continue to: rotate until the wiper findsan idle primary switch, such as shown at C Fig". 2. As soon as such anidle switch is found. relay 5 is placed in series with relay 21 (Fig. 2)by the followingpath: ground, contact of relay 4, 5, 18, 7, 14, 21, 70,contact of relay 24 to battery.

Just before reaching its The relay 5 becoming energized, opens thecircuit of the stepping magnet 7, bringing the switch V to rest. Relay21 operating closes the circuit of the rotary stepping magnet 31 by thfollowing path: battery B, 80, back contact of relay 24, 71, contact ofrelay 28, back contact of relay 22, 31 to ground. The operation ofmagnet 31 causes the primary switch C to rotate until the wiper 64reaches the busy contact connected to the wire 13. The wiper 64 iscarried on the same spindle with wipers 63 and 65. While the switch isrotating, the wiper 64 passes over contacts leading to the group relay3. As there are ten of these group relays to each one hundred lines, itfollows that the wiper 64 can come into engagement with any one of tencontacts.

There are ten sets of individual contacts arranged in vertical rows,associated with each row contact which the wipers 63 and 65 respectivelyengage. It therefore follows that after the switch picks out the groupin which a line is calling, it will afterward step vertically until thewipers engage the contacts of the calling line. As soon as the rowcontact is found, the circuit of relay 22'is closed as follows: battery13, 80, 71, 22, 64, 13, contact of relay 3 to ground. nects the rotarymagnet 31 and in its place connects the vertical magnet 30, therebycausing the switch to step vertically until the busy individual testcontact is found. As soon as the latter contact is found, the relay 24is energized by the following path: battery 13, 24, 68,-contacts ofrelay 22, 67, 11, contacts of relay 2 to ground through the contacts ofrelay 1. The relay 24 operat- The relay 22 operating, disconing opensthe wire 71 and disconnects relay 22. Relay 22, in falling back,disconnects relay 24 from wire 67 and connects it instead to wire 66,thereby placing the relay 24 in series with relay 1. The operating ofrelay 1 now disconnects the line relay 2 and also the group relay 3. Theoperating of relay 24 connects battery to the windings of relays 23, and25 and the falling back of relay 22 connects ground to the retardationcoil 26, thereby supplying the calling subseriber with talking battery.The relay 21 remains energized until the primary switch finds thecalling line, and until the key-set switch finds the trunk. The relay 21when first actuated placed battery on the wire 79 to relay 130, toground, and also placed battery to wire 62 leading to individual testcontact of th key-set switch (Fig. 6). The relay 130 operating closesthe circuit'of the stepping magnet 133 of the switch Y through thenormally closed contacts of relays 131 and 132. The switch magnet inoperating closes the circuit of the inter rupter relay 134, which causesa Vibrating effect between the magnet and the relay 134.

The switch will continue to rotate until the idle key-set switch isfound. As soon as such a switch is found as shown in Fig. 6, relay 131is placed in series with relay 152, (Fig. 6), by the following path:ground, contacts of relay 130, 131, 138. Y, 140, 152, 195', 196, 197 tobattery through the operators jack.

Relay 131 operating places battery on wire 136 to relay 132, causing itto operate. As soon as this relay operates, it places ground on wire138, thereby shunting relay 131. This direct ground placed on wire 138makes the wire 140, which is multipled to other Y switches busy. Theoperating of relay 132 also places ground on the row wiper of therey-set switch by the following path: ground, 139, Y, 141 to the rowcontact.

Relay 152 operating places ground on the rotary magnet 165 through theback contact of relay 153, thereby causing the switch M to rotate. Theswitch will continue to rotate until the busy row cont-act is found,whereupon the circuit of the relay 153 will be closed by the followingpath: battery 13, contacts of relay 152, 176, 153, 171, 168, 141, 139,contacts of relay 132 to ground. The key-set switch M operates in thesame manner as the primary selector switch C (Fig. The operating ofrelay 153 disconnects the rotary magnet 165 and in its place connectsthe vertical magnet 164, thereby causing the key-set switch to stepvertically until the busy individual test contact is found. As soon asthis contact is found, the circuit of relay 154 is closed by thefollowing path: ground, 154, 172, 62, 80, contacts of relay 21 tobattery B. The operating of relay 154 disconnects relay 152, therebycutting 02 the vertical magnet, causing the key-set switch to rest oncontacts leading to the calling primary trunk. Relay 152 becomingdisconnected, opens circuit of relay l53 and this latter relay infalling back places the relays 156 and 25 in series by the followingpath: ground, back contact of relay 153, 175, back contact of relay 157,202, back contact of relay 155, 156, 193, contacts of relay 158, 170,59, 25 to battery B through the contacts of relay 24.

The operating of relay 25 (Fig. 2) disconnects relay 21 and relay 5(Fig. 1). The releasing of relay 5 frees the switch WV, allowing it topick out other primary switches. Relay 156 operating places battery onwires 181 and 183, thereby causing the lamps 243, and 244 (Fig. 7 tolight. As soon as relay 21 in Fig. 2, became disconnected battery wasremoved from the individual test contact of the key-set switch,

allowing relay 154 to fall back. The fall- 'ing back of relay 21releases relay 130, thereby restoring relay 132 so as to allow theswitch Y to be used by other trunks, in picking out key-set switches.

In the present system, I have provided ten primary switches, as shown inFig. 2, for each 100 lines. Each group of ten primary switches, as inFig. 2, is provided with one Y switch which picks out an idle key-setswitch. The wire 141, leading from the Y switch to the row contact ofthe keyset switch, is multipled. As soon as the Y switch picks out akey-set switch, ground is placed on the row contact of the selectedswitch. This prevents interference in case other Y switches, associatedwith other trunks, are picking out other switches. In no case is groundplaced on more than one row contact of any key-set switch at the sametime. This method allows calls to come from different groups of trunksat the same time, and yet prevents interference between key-setswitches.

In Fig. 1, the W switch is individual to one hundred lines and picks outa group of primary switches and in this case the row contacts of a groupare multipled, as only one primary switch at a time is started in searchof the calling line. The percentage and grouping of the primary switchescan be increased or decreased to suit traffic conkey-set ditions. Thelighting of the two lamps 243,

and 244 notifies the operator of a call and she then presses the button248 operating relay 155, thereby connecting her telephone set across thetip and sleeve conductors of the trunk. The operating of relay 155disconnects relay 156, thereby extinguishing lamps 243, and 244, but atthe same time lamp 245 is lighted. Relay 156 being disconnected allowsrelay 25 (Fig. 2) to fall back, closing the tip and sleeve conductors ofthe trunk, allowing the operator to converse with the callingsubscriber.

If the calling party desired to converse with some one in thesemi-automatic exsired to converse with some one in the semiautomaticexchange, the first selector switch D (Fig. 2) would rotate until thewipers came to rest in line with contacts leading to second selectorswitches, and then automatically pick out an idle one. After the secondselector switch was picked out, it would change, the operator would setup the proper in turn pick out an idle connector which would pick outthe line of the called party in the regular manner.

I have not shown second selectors or connector switches, as they form nopart of the present invention.

If the calling party wishes to converse with a party in a manualexchange, the operator sets up on her key-board first the number orlocation of the exchange which would be represented in the row ofbuttons R. She would then set up a button in the row S corresponding tothe hundreds, a button in the row T corresponding to the tens, a buttonin the row U corresponding to the units, and finally a button in the rowV corresponding to the party line, letter or numher.

In the present instance, I have shown the manual exchange to be of onethousand lines capacity, and in case of a larger exchange, it would onlybe necessary to add additional rows of buttons to the operators key-setand additional indicators or number wheels before the operators at themanual exchange.

Ten buttons are shown in the row V, but the selective ringing device inFig. 3 is only arranged to select any one of four kinds of ringingcurrent. The cams of this same device, however, could readily bearranged so as to perform any method of party line ringing. Theoperator, after getting the proper number at the manual exchange, andpressing the corresponding buttons, then presses the button 247. Thisbutton closes the circuit of the starting relay 157, by the followingpath: ground 247, 186, 157, 193, 170, wiper 169, 59, 25, to battery Bthroughthe contacts of relay 24. The relay 25 again operating, opens thetrunk conductors and prevents the calling party from hearing theimpulses. The operating of relay 157 disconnects the relay 155,extinguishing lamp and causing the guard lamp 244 to light. Relay 157also connects the starting wire 189, to contacts operated by the cam231, to the stepping magnet 161. As soon as the contact springs areoperated by the cam 231, the wipers of the shifting switch take one stepand connect the impulse wire 191 to the tip side of the trunk 150through the contacts of relay 160. v

i If the trunks leading to the manual exchange are in the tenth row ofcontacts in the first selector switch (Fig. 2) and the operator haspressed No. 10 button in the row R, the relay 160 will be held energizedby the operation of the cam 241 until ten impulses have been transmittedby the commutator 242. These impulses operate the rotary relay 29 (Fig.2) by the following path: ground, 242, 191, 190, 192, contacts of relay160, 198, N, 150, 167, 60, 54, 29, cam springs 40 to battery B. Therelay 29 responding to these impulses, closes the circuit of the rotarymagnet 34, causing the first selector switch D to rotate and comeopposite a group of trunks leading to the manual exchange. After theserotary impulses have been sent, the starting cam 231 causes the shiftingswitch to take another step, thereby connecting the wire 198 to thesleeve side of the trunk 151. The relay 160 now receives a single testimpulse caused by the action of the cam 230. This impulse operates therelay 27 (Fig. 2) by the following path: ground, 242, 191, 190, 192,contacts of relay 160, 198, N, 151, 167, 61, relay 27, cam springs 40 tobattery B. The relay 27, receiving this impulse, is held energized bythe following path: battery B, contacts of relay 25, locking contacts ofrelay 27, 58, contacts of relay-28, 72 to ground through cam springs 41,as these latter cam springs were operated when the switch took its firstrotary motion. The operating of this relay 27 closes the circuit of thevertical magnet 33 by the following path: battery B, contacts of relay28, 71, contacts of relay 27, 33, to ground. The magnet 33 in operating,closes the circuit of'the relay 28, which in turn opens-the circuit ofthe magnet 33 itself. The action of this relay and magnet causes thelatter to vibrate, stepping the switch D vertically. hen the circuit ofthe relay 28 is closed by the action of the magnet 33,'the relay-27 hasits circuit partially opened, but it will remain energized by the testwiper 57 in passingover ground or busy contacts. If, while the magnet 28is operated, the wiper 57 comes to rest on an idle contact, the relay 27will at once become deenergized and disconnect the vertical magnet 33.As soon as the switch D takes its first vertical step, or while it is inthe act of taking this step, the cam springs 40 are opened, therebydisconnecting relays 27 and 29 respectively from the tip and sleevesides of the trunk. The relays 36 connected to test contacts leading tothe manual exchanges, are of a high resistance, so as not to render thecontacts to which they are connected busy. After the test wiper 57 picksout an idle trunk, the subscriber is connected to the manual exchange.

At the third rotation of the sending device, impulses corresponding tothe hundreds are sent over the tip side of the trunk to the manualexchange operating relay 98. This relay closes the circuit of theindicating magnet 284 by the following path: battery B, contacts ofrelay 98, 123, E, 260, 284 to ground. This indicator magnet operatingcauses a suitable number wheel to register the proper number. Theindicators used are of the type commonly known as Veeder counters. Therelay 98 operating closes the circuit of the locking or control relay82. This latter relay disconnects the commutator 89. and also closes thecircuit of relay 96. Relay 96 operating severs wires 280, 281, 282 and283.

At the fourth rotation of the sending device, a single test impulse issent over the sleeve side of the trunk to the manual exchange operatingrelay 81. This relay closes the circuit of the stepping magnet 88,causing the switch X to take one step, thereby disconnecting indicatorH, and in its place connecting indicator 1. At the fifth rotation of thesending device, relay 98 operating closes the circuit of the magnet2285, thereby registering another digit corresponding to the tensnumeral of the wanted line. At the sixth rotation, 21 single testimpulse operating relay 81 causes the switch X to take another step,disconnecting the indicator 1, and in its place connecting the indicatorJ. At the seventh rotation of the sending device, relay 98 is operatedcausing the magnet 286 to register the units numeral of the wanted line.

At the eighth rotation of the sending device, the switch X takes anotherstep, disconnecting the indicator J and in its place connecting theselective ringing device K. At the ninth rotation of the sending device,the magnet 102 operating causes the selective ringing device to steparound and connect the proper generator to the ringing relay 95. I

We will assume for illustration that the fourth generator 279 is the oneto be selected.

The first step of the device caused by the action of magnet 102 operatescams 100 and 101. The cam 100 in operating, brings the projection 110into engagement with spring 103, thereby closing contacts 103 and 104,connecting the first generator 276. At the next step, the projection 120on the earn 101 engages spring 107, thereby connecting springs 106 and107. however, the spring 103 leaves projection 110 and rests on thesurface 112, disengaging spring 103 from contact 104. At the third stepthe spring 103 enters the detent 111 of the cam 100, thereby closingcontacts 103 and 105. At the same instant the spring 107 rests on thesurface122, thereby breaking contact with spring 106. At the fourthrotation, the spring 107 enters the detent 121 of the cam 101 andengages contact 108, but at the same time spring 103 rides on thesurface of the cam 100 and disengages contact 105. The fourth generator279 is now connected to the contact of the ringing relay 95. At thefirst step of the indicators or registers, the lever springs leave thedepressions 114, 115, 116, and 117 respectively and ride upon thesurface of their respective cams and close the springs associated Withwires 280, 281, 282 and 283. The sending device now takes one more step,sending a At the same time,

single test impulse over the sleeve side of the trunk, causing theswitch X to take one more step, closing the circuit of the signal lamp87 by the following path: ground, F, 265, contacts of relay 84, 271, 87,to battery BB. As soon as the shifting switch in Fig- 6 takes this finalstep, the wiper of the bank P closes the circuit of relay 158 by thefollowing path: battery B, 187, 158 to ground. The operating of thisrelay connects ground to the magnet 161, and also opens the circuit ofrelay 157. Under the influence of the magnet 161 the shifting switchstarts to rotate and continues to do so until itreaches its normalposition. Just before reaching its normal position the wiper of the bankP connects the relay 158 in serieS with release magnet 166, causing thelatter to operate and release the switch M. This switch releasingdisconnects the operator in the semi-automatic exchange from the primarytrunk, (Fig. 2).

The lighting of the lamp 87 at'the manual exchange notifies the operatorof a call and she thereupon places the plug PP into the jackcorresponding to the number registered on the indicator. In case thejacks 400 at the manual exchange were multipled, the operator wouldfirst test the line to find whether it were busy, and if so, would placethe plug into the busy-back jack, which would indicate to the callingsubscriber that the wanted line was busy. If the wanted line is notbusy, the operator places the trunk plug into the jack of the wantedline, thereby placing relays 84 and 401 in series. The operating ofrelay 401 disconnects the line signal relay and connects the linethrough to the jack. The operating of the relay 84 connects thecommutator 90 to the ringing relay 95 by the following path: ground, 90,contacts of relay 84, 269, contacts of relay 85, 128, to battery BB.Relay 84 also disconnects the lamp 87 and at the same time closes thecircuit of the lamp 86 through contacts of relay '83. The operation of95 at intervals severs the cord circuit and places generator current tothe called line, ringing the telephone, which responds to generator 279.The called subscriber removing his receiver during the ringing intervalenergizes relay 83, thereby disconnecting lamp 86, and energizing relay85. The energizing of relay 85 disconnects the ringing relay 95, therebypreventing any further action of the same. The calling and calledsubscribers are now enabled to conv verse. The energizing of relay 83disconnects relay 96, thereby connecting the interrupter or commutator89 to magnets 284, 285. 266 and 102. Each of these magnets will continueto vibrate until the lever springs enter the depressions 114, 115, 116and 117 respectively.

hen the called subscriber hangs up his receiver, the lamp 86 is againlighted and the calling subscriber upon hanging up his receiver releasesthe automatic switches, at the semi-automatic exchange and operates thelamp S7, notifying the operator that he is through talking. \Vhen thecalling subscriber hangs up relay 23 (Fig. 2) falls back and closes thecircuit of the release magnet 32 by the following path: battery B, 38,74, contacts of relay 23, 58, contacts of relay 28, 7 2, 32, 7 5, 41 toground. The action of this relay releases the primary switch C. Batteryis also placed on relay 36 by the fol lowing path: battery B, 38, 7 3, 71-, contacts of relay 23, 58, 57, 78, 36 to ground. The action of thisrelay places ground on wires 7 6, and 77 leading to the manual exchange,simultaneously energizing relays 81 and 98. The joint action of thesetwo relays unlocks relay 82, which upon falling back closes the circuitof the lamps 87 by the following path: ground, 267, contacts of relay 34271,

S7 to battery BBX The operator upon ge ting the signals, removes theplug PP from the jack, thereby deenergizing relay 84-, which unlocksrelay S5 and extinguishes lamps 86, and 87. As soon as the switch 0restores, opening the springs 38, the two magnets 32 and 35 are placedin series by the following path: battery B, 35,73, 74:, contacts ofrelay 23, 58, 72, 4-1, 32, 75, all to ground. The action of magnet 35causes the switch D to restore.

In connection with the apparatus and circuits shown in Fig. 3, it willbenoted that I have the various indicators released by the commutator89, but in practice, it would be preferable to have each indicatingmagnet provided with its own interrupter or vibrating springs, similarto those of the ordinary vibrating door bell. IVith this latterarrangement, each magnet would control its own circuit and actindependently of the others.

Instead of releasing the indicators with interrupted current, I canprovide the inclicators with suitable return springs and re leasemagnets for restoring purposes. The switch X can also be provided with are-. lease magnet.

The switch X (Fig. 3) is restored when the called party answers by meansof inter rupted current from the commutator 89 directly through thecontacts of relay 83. lVire 126, however, instead of leading to acontact in relay 83 can terminate in a contact of relay 96 as do wires281, 282, 283 and 280.

The particular form of selective ringing device as shown, is simply usedfor illustration, but forms no part of my invention.

Instead of using the cam arrangement, as shown in the device at K, I canprovide a switch similar to X, which will step its wipers around andpick out the generator current in the same manner in which the switch Xsteps around to pick out the proper indicator. This switch would berestored in the same manner by a bank and wiper corresponding to G. Theswitch X continues to rotate for restoring purposes until the wiper Gcomes to rest on an idle contact 600, thereby opening the commutatorcircuit.

In case the called for party at the manual exchange does not answer,then the calling party upon hanging up releases relay 82, which uponfalling back disconnects relay 96 and connects the commutator to thestepping magnets of the indicators and the switch X.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a telephone exchange system, an exchange having a plurality 0tvsubscribers lines associated therewith, a second exchange having aplurality of subscribers lines associated therewith, a plurality ofdigit indicators at such first exchange capable of representing therespective designations of the subscribers lines of said first exchange,setting means for said indicators controlled over an impulse circuitincluding one conductor of a trunk line connecting such exchanges, andmeans for shifting said w setting means from one digit indicator toanother, controlled over another conductor of such trunk line.

2. In a telephone exchange system, an exchange having a plurality ofsubscribers lines connected therewith, a second exchange having aplurality of subscribers lines connected therewith, an indicator at thefirst exchange having a number of digit wheels representing digitnumerals, and means for operating said digit Wheels successively fromthe second exchange, said means including trunks, trunk selectorswitches, a sending machine, and a keyboard, together with step by stepswitching apparatus to successively associate the digit wheels with thetrunk.

3. In a telephone exchange system, an exchange having a plurality ofsubscribers lines connected therewith, a second exchange having aplurality of subscribers" lines connected therewith, and a trunkprovided with an indicator at the first exchange capable of representingthe respective designations of the subscribers lines of said exchange,and means for controlling the indicator, and also provided with meansfor automatically ringing the indicated subscriber when connection ismade with his line.

4c. In a telephone exchange system, an exchange having a plurality ofsubscribers lines connected therewith, a second exchange having aplurality of subscribers lines connected therewith, a trunk providedwith an indicator at the first exchange capable of representing therespective designations of the subscribers lines of said exchange, meansfor controlling the indicator, and also provided with means forautomatically ringing the indicated subscriber when connection is madewith his line, selector switches for controlling the connection be tweenexchanges over the trunk, and means for automatically disconnecting theringing means when the called subscriber answers.

5. In a telephone system, the combination of an automatic exchangeincluding a plurality of subscribers lines, automatic switches, a keyboard associated with said switches for directively controlling theselective action of the same, a manual exchange, an indicator at saidmanual exchange, adapted to display the numbers of called lines in themanual exchange, a signal associated with said indicator and means foroperating said indicator to display the number when the same is set upon the key board of the automatic exchange and means for displaying saidsignal after the complete number is displayed by said indicator,

6. In a telephone system in combination, an automatic exchange includinga plurality of subscribers lines, and automatic switches, together witha key board directly controlling the selective action of the saidswitches, a manual exchange, trunk lines connecting the manual exchangewith the automatic exchange through said automatic switches, said trunklines terminating at the manual exchange in cord circuits and anindicator at said manual exchange adapted to display the numbers ofcalling lines, and operable through said automatic switches and saidtrunk lines from said key board. 7

7. In a telephone system in combination, an automatic exchange includinga plurality of subscribers lines and automatic switches, together withakey board for directively controlling the selective action of theswitches, another exchange connected with said automatic exchange, anindicator at said other exchange adapted to display the number of calledsubscribers lines, together with controlling connections from said keyboard of the automatic exchange to said in dicator, whereby saidindicator may be operated to display the number of the wanted line bythe setting up of said number upon said key board, means apart from saidindicator to indicate the number has been displayed.

8. In a telephone system in combination, an automatic exchange includinga plurality of subscribers lines, automatic switches, a key board fordirectively controlling the selective action of said switches, anotherexchangehaving a plurality of subscribers lines, trunk lines connectingsaid other exchange with said automatic exchange through certain of saidautomatic switches, and an indicator adapted to display the number ofcalled lines located at said other exchange and operable from said keyboard of the semi-automatic exchange through said automatic switches andcomiecting trunks, means for associating said indicator with the calledlines, and means exercised said sending device through said automatic;

switches and over said trunk lines, releasing means for said indicator,and means ex ercised over said trunks for controlling said releasingmeans.

10. In a telephone system in combination, an exchange comprising aplurality of subscribers lines, a plurality of automatic switches, asending device for directively controlling the selective action of theswitches, and an indicator adapted to dis play the number of a calledline accessible through said automatic switches and operable t'roni saidsending device, together with automatic polystation ringing meanssimilarly accessible and similarly operable.

11. In a telephone exchange system, a plurality of subscribers lines,central station means for interconnecting the same, an indicator at saidcentral station, a sending device adapted to operate said indicatortodisplay the number of the called line, and means associated with saidcentral station connecting means and operating upon the response of thecalled subscriber to release said indicator.

12. In a telephone exchange system, a plurality of subscribers lines,central station means for interconnecting'the same, an lndicator at thecentral station adapted to display the numbers of called'lines, asending device for operating the said indicator, and a polystationringing means operated in conjunction with said indicator from saidsending device.

13. In a telephone exchange system, a

plurality of subscribers lines, central station means forinterconnecting the same, an indicator at the central station adapted todisplay the number of called lines, a sending device for operating thesaid indicator, a polystation ringing means operated in conjunction withsaid indicator device from said sending device, and means associatedwith said central station connecting means operating when the calledsubscriber answers to disable said polystation ringing means and releasesaid indicator.

14:. In a telephone exchange system, a plurality of subscribers lines,central station means for interconnecting the same, an indicatorassociated with said central station means, and comprising digit displaydevices connected individually with a step by step switch, a sendingdevice adapted to operate said step by step switch and to operate saiddigit display devices through said step by step switch in succession,together with polystation ringing means also selectively operablethrough said step by step switch from the sending device.

15. In a telephone exchange system, a plurality of subscribers lines,central station means for interconnecting the same, an indicator adaptedto display the numbers of called lines, a sending device, a step by stepswitch through which said indicator may be actuated from the sendingdevice, said step by step switch having a defined normal position, meansoperative upon response of 2. called subscriber to release saidindicator, and means controlled by the calling subscriber to return saidstep by step switch to normal.

16. In a telephone exchange system, the combination with an exchange anda plurality of subscribers lines, of an indicator at the exchangeadapted to represent the respective designations of the subscriberslines, said indicator having a number of digit wheels and a magnet foreach -of said wheels, means for predeterminedly operat ing said magnetsin succession to display the designations of the subscribers lines, andmeans controlled by said magnets for restoring said digit wheels.

17. In a telephone exchange system, a plurality of subscribers lines, acombined indicator and a polystation ringing device, means for operatingsaid indicator to display the numbers of the called lines and forsignature l WVitnesses:

ARTHUR L. BRYANT, J. A. WATSON.

Copies of this patent may be obtained for five cents each, by addressingthe commissioner of Patents Washington, D. G.

